System and method for delivering short message service text to call centers

ABSTRACT

A wireless emergency system that includes a mobile switching center, a short message service center that receives an emergency text message of a caller from the mobile switching center, and gateway in communication with the short message service center to route the emergency text message to a responsive public safety answering point as a tone message.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/808,458, titled “System And Method For Delivering TextMessages To Call Centers” filed on Jul. 24, 2015, now allowed; which isa continuation of U.S. patent application Ser. No. 13/221,507, titled“System And Method For Delivering Short Message Service Text To CallCenters” filed on Aug. 30, 2011, and issued as U.S. Pat. No. 9,094,811on Jul. 28, 2015, the entire content of each of which is hereinexpressly incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to delivery of messages and other media tocall centers, such as emergency call centers.

BACKGROUND

Cellular phone users (especially younger users) increasingly communicatevia short message service (SMS) text messaging instead of placingtelephone calls. Although emergency call systems (e.g., 9-1-1, 1-1-2,9-9-9) do not support SMS, there is an expectation by many users that“text to 9-1-1” functionality has been incorporated into text messagingnetworks already.

In many circumstances, sending an SMS text message to 9-1-1 would beless effective or less efficient than placing a phone call. Of course,SMS text messages require that messages be typed so as to becommunicated over a network, whereas a voice call occurs in real time.Accordingly, voice calls can be more effective for quickly communicatingan emergency to an emergency call center. But, there are some emergencycircumstances where texting is necessary, such as instances when a usermay not be able to speak, but may be capable of sending text messages.

The infrastructure for known emergency call systems has been designedfor handling voice calls, rather than a text-based interface. FIGS.1A-1C are block diagrams that illustrate conventional arrangements ofcomponents in present emergency call systems for handling emergencyvoice calls. The block diagrams illustrate conventional signaling pathsbetween landline, mobile, and voice over Internet protocol (VoIP)telephones and a public-safety answering point (PSAP), which is callcenter responsible for answering calls to an emergency telephone numberfor police, firefighting, and ambulance services.

FIG. 1A illustrates a conventional landline emergency call system 1 a.Landline telephones 11 establish calls by connecting to a local exchange21. The local exchange 21 is a telephony switch that performs switchingfunctions for landline telephones connected to the local exchange 21.The local exchange 21 identifies calls addressed to 9-1-1 and routesthese calls to a 9-1-1 selective router (SR) 70 as a typical voice callusing the SS7 signaling protocol. The 9-1-1 SR 70 then routes theemergency call to PSAP 80 using multi-frequency (MF) tone signaling.Here, the 9-1-1 SR 70 also identifies the appropriate PSAP 80 to receivethe call. To do so, the 9-1-1 SR 70 maintains a table assigning a PSAPto each of landline telephones 11. During an emergency call, a calltaker at PSAP 80 may require the caller's location to dispatch emergencyservices to the caller. In order for the PSAP 80 to determine thecaller's location, the PSAP 80 can query the automatic locationidentification system (ALI) 92. The ALI 92 is one or more computerscontaining a database that stores the street address of every landlinetelephone.

FIG. 1B is a block diagram that illustrates a conventional signalingpath between mobile user equipment (UE) and a PSAP. The conventionalemergency call system for cellular telephone systems was developed towork within the already developed landline emergency call system 1 a.

In the conventional cellular emergency call system 1 b depicted in FIG.1B, the UE 10 communicates with a mobile switching center (MSC) 20through a base station (not shown). Typically, the UE 10 is a cellulartelephone, smartphone, or the like. The MSC 20 is a server or aplurality of servers that performs switching and management functionsfor UEs connected to a cellular network. The MSC 20 identifies callsaddressed to 9-1-1 and routes these calls to a mobile positioning center(MPC) 91. The MPC 91 is a server or plurality of servers dedicated toassisting placement of emergency calls. Upon being notified of a calladdressed to an emergency number (9-1-1), the MPC 91 determines anappropriate PSAP 80 to receive the emergency call based on the UE'slocation (as discussed below). The MPC 91 then instructs the MSC 20 toroute the call to 9-1-1 SR 70 as a typical voice call using the SS7signaling protocol. The 9-1-1 SR 70 then routes the emergency call tothe PSAP 80 using MF signaling.

The MPC 91 also allocates a 10 digit number to the UE 10. The number iscalled a “pseudoANI” or “pANI”, which has an area code appropriate forthe PSAP 80. The actual telephone number of the UE 10 cannot be usedbecause the PSAP 80 does not support non-local area codes. The pANI isneeded because a UE in a cellular network is mobile and may often be ata location where the telephone number associated with the UE is anon-local telephone number. The MPC 91 maintains a pool of sucharea-code appropriate pANIs for each PSAP. When a call arrives for thePSAP, one of the pANIs from the pool associated with the PSAP isallocated for use during the emergency call. When the call is over, thepANI is returned to the pool, and may be reused for another call to thesame PSAP.

The MPC 91 and PSAP 80 are each connected to ALI 92. To request thecaller's location, the PSAP 80 sends a query message to the ALI 92 usingthe pANI assigned to the call. The ALI 92 sends the query message to theMPC 91. The MPC 91 communicates with the PDE 93 in order to obtain thelocation of a UE. The PDE 93 is a cellular network element that obtainslocation measurements from the UE 10, such as global position systemmeasurements, or from various forms of triangulation from the cellulartowers to determine the latitude and longitude of the UE 10.

A rough location of a caller may also be determined using the cell ID,which includes the cell and sector currently serving the UE 10. Mobileemergency calls are typically routed based on the cell ID, and notnecessarily on the closest PSAP to the user or the tower. A databasethat stores cell IDs and corresponding PSAPs is maintained at the MPC91. The MPC 91 determines an appropriate PSAP to receive the emergencycall by retrieving the PSAP 80 from the database based on the UE'sserving cell ID.

FIG. 1C is a block diagram that illustrates a conventional signalingpath between a VoIP telephone 12 and a PSAP. The conventional emergencycall network for VoIP phone systems was also developed to work withinthe already developed landline emergency call network 1 a.

In the conventional VoIP emergency call system 1 c depicted in FIG. 1C,the VoIP telephone 12 communicates with a call server 22 through anInternet connection. The call server 22 is a server or a plurality ofservers that performs switching functions for VoIP telephones connectedwithin the VoIP telephone network. The call server 22 identifies callsaddressed to 9-1-1 and routes these calls to a voice over IP positioningcenter (VPC) 50. The VPC 50 is a server or plurality of serversdedicated to receiving emergency calls from the call server 22 usingVoIP. Upon receiving a call addressed to an emergency call center, theVPC 50 determines an appropriate PSAP 80 to receive the emergency callbased on the UE's location (as discussed below). The VPC 50 then routesthe call to an emergency services gateway (ESGW) 60. The ESGW 60 is agateway that receives the emergency call using VoIP and routes the callto a 9-1-1 SR 70 as a typical voice call using the SS7 signalingprotocol. The 9-1-1 SR 70 then routes the emergency call to the PSAP 80using MF signaling.

The VPC 50 also allocates a pANI to the UE 10. As is the case withcellular phones, a pANI is needed because the actual telephone number ofthe VoIP telephone cannot be used because the PSAP 80 does not supportnon-local area codes. The pANI is needed because a VoIP telephone may beat a location where the telephone number associated with the VoIPtelephone is a non-local telephone number.

To request the caller's location, the VPC 50 sends a query to thelocation information server (LIS) 94. The LIS 94 is one or more serverscontaining a database that stores the street address of every VoIPtelephone. The VPC 50 and PSAP 80 are each connected to the ALI 92. ThePSAP 80 can also query the caller's location. To do so, the PSAP 80sends a query message to the ALI 92 using the pANI assigned to the VoIPtelephone 92. The ALI 92 sends the query message to the VPC 50. The VPC50 relays the query to the LIS 94 in order to obtain the location of aVoIP telephone 12.

The infrastructure for known emergency call systems has been designedfor handling voice calls, rather than a text-based interface. As anexception, emergency 9-1-1 systems accommodate use of text telephones(TTY), also known as text devices for the deaf (TDD), to enable allowsdeaf persons to contact emergency call centers. TTYs are text devicesthat use conventional analog telephone lines, and encode text on ananalog phone call using tones, such as Baudot tones. In this manner,TTYs use tones on regular voice calls to convey text on an emergencyvoice call. A TTY uses a Baudot code or another code such as ASCII, sentby a 45.45 bps binary frequency-shift-keyed scheme that is carrierless,half duplex, and without error protection. All emergency call centershave one or more TTYs (as required by the Americans with DisabilitiesAct), and many have the capability to receive TTY calls at every calltaker's position in the call center, although the use of TTY by the deafis currently being phased out with other advances in technology.

Since existing emergency call centers are not able to accept SMScommunications, upgrading the centers themselves to provide“text-to-9-1-1” functionality would be expensive and would require yearsof time for deployment. Therefore, it is desirable to provide anarrangement that enables texting of SMS messages to PSAPs withoutrequiring upgrades of the emergency call centers themselves.

Accordingly, certain embodiments of the present invention are directedto systems and methods for delivering SMS and other media to callcenters, including emergency call centers, which utilize existinginfrastructure. Embodiments of the invention can use TTYs in the PSAPsto provide SMS capability in the UEs by interworking the SMS messagesystem with the TTY support system in the emergency call process, thusallowing a wireless caller to text to the PSAP in the same way thecaller would text to anyone else, which then allows the PSAP to use itsTTY in the same way as any other TTY call.

SUMMARY OF THE INVENTION

Accordingly, embodiments of the present invention substantially obviateone or more problems due to the limitations and disadvantages identifiedabove.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, the systemand method for delivering short message service text to call centersincludes a wireless emergency system including a mobile switchingcenter, a short message service center that receives an emergency textmessage of a caller from the mobile switching center, and gateway incommunication with the short message service center to route theemergency text message to a responsive public safety answering point asa tone message.

In another aspect, the system and method for delivering short messageservice text to call centers includes a gateway for routing a textmessage including a text message receiver that receives an emergencytext message of a caller from a short message service center, atranscoder that exchanges text messages with the short message servicecenter and exchanges tone messages with a responsive public safetyanswering point, the transcoder bi-directionally translating betweentext message and tone message formats, and a text message transmitterthat transmits a reply text message to the caller that corresponds to atone message received from the responsive public safety answering point.

In yet another aspect, the system and method for delivering shortmessage service text to call centers includes a method for routing atext message including receiving an emergency text message of a caller,generating an emergency tone message corresponding to the emergency textmessage, and sending the emergency tone message to a responsive publicsafety answering point.

In yet another aspect, the system and method for delivering shortmessage service text to call centers includes a wireless messagingsystem comprising a means for receiving text messages of a callerintended for a call center, and a gateway means in communication withthe receiving means for routing selected text messages to a call centeras a tone message.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention. In the drawings:

FIG. 1A-1C are block diagrams that illustrates conventional arrangementsof components in an emergency call network for handling emergency voicecalls;

FIG. 2A-2D are block diagrams illustrating exemplary emergency callsystems in accordance with embodiments of the present invention;

FIG. 3 is a block diagram that illustrates an exemplary gatewayaccording to an embodiment of the present invention; and

FIG. 4 is a flow diagram that illustrates an exemplary method forconnecting with a public safety answering point in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, like reference numbers will be used forlike elements.

FIG. 2A is a block diagram that illustrates an exemplary emergency callsystem in accordance with an embodiment of the present invention.

In this embodiment of the present invention, the Gateway 140 isintroduced to interconnect the SMS system with the cellular and VoIPemergency call systems. Accordingly, as shown in FIG. 2A, the exemplaryemergency call system includes user equipment (UE) 110, mobile switchingcenter (MSC) 120, short message service center (SMSC) 130, Gateway 140,voice over IP positioning center (VPC) 150, emergency services gateway(ESGW) 160, 9-1-1 selective router (SR) 170, PSAP 180, mobilepositioning center (MPC) 191, automatic location identification system(ALI) 192, and position determining equipment (PDE) 193.

Emergency call system 100 in accordance with an embodiment of thepresent invention as depicted in FIG. 2A includes Gateway 140 forestablishing and maintaining text communication sessions with the PSAP180 (and as described below, for providing other media from a UE to thePSAP). During a communication session, SMS text messages are sent to thePSAP 180 using a tone format. The Gateway 140 is a computer havinghardware and software components to transmit and receive text messagesas well as transcode the SMS text messages to a tone format that can betransmitted on an audio call session with the PSAP 180. A more detaileddescription of Gateway 140 can be found in the discussion of FIG. 3.Unlike conventional SMS gateways, Gateway 140 interfaces with anemergency call network (or other call center) to transmit data on anaudio channel using tones.

FIG. 2A additionally includes SMSC 130 for delivering SMS text messagesfrom the UE 110 to the Gateway 140. Although SMSCs are known elements ofa wireless network for delivering SMS text messages between user UEs, inaccordance with an embodiment of the invention, the SMSC is incorporatedinto the emergency call system. In accordance with an embodiment of theinvention, MSC 120 is provisioned to translate the ‘911’ dial string tothe address of Gateway 140, typically a 10 digit telephone number. Thistelephone number will route SMS text messages in the wireless network tothe proper SMSC 130, which will route it to Gateway 140. The MSC 120performs similar translation for other “short codes” (e.g., 311 and *86)for reaching other call centers. The MSC 120 contains a translationtable that translates short codes to 10 digit TNs.

As depicted in FIG. 2A, an SMS text message originating at UE 110 isreceived by the MSC 120. If the text message is addressed to 9-1-1, theMSC 120 translates the 9-1-1 code to a telephone number of Gateway 140and sends the emergency SMS text message to the SMSC 130. The SMSC 130,recognizing the telephone number of the Gateway 140, can send themessage to the Gateway 140. In other words, the emergency text messagecan be routed to Gateway 140 through the SMSC 130. Upon receiving theemergency SMS text message, Gateway 140 can determine whether theemergency SMS text message is an initial message to establish acommunication session or is otherwise part of an existing communicationsession with the PSAP 180. If Gateway 140 determines that the emergencytext message is an initial message, then a communication session withthe PSAP 180 is established. The caller is identified by the telephonenumber associated with the UE 110. When a caller sends an initialmessage, a communication session is not yet established. Gateway 140maintains a table of communication sessions with the telephone number ofthe caller for each session. When a message is received, the Gateway 140checks the telephone number of the message sender against the telephonenumbers of the existing communication sessions. If this is an initialmessage, there will not be a match. Gateway 140 then establishes a newcommunication session and associates the caller's telephone number withthat session. Subsequent messages to and from the same caller will beidentified as being within this session.

In accordance with an embodiment of the invention, the “session”includes the audio call to the PSAP 180, such as a VoIP call. While avoice call has a definite beginning and ending, SMS text messages donot. Rather, each SMS text message is an independent exchange ofinformation. Accordingly, a session starts when a first message from anew telephone number is received at Gateway 140, and ends when the PSAP180 terminates the audio call. If another text message from the sametelephone number is received by the Gateway 140 after the termination ofthe audio call, it is treated as a first message by Gateway 140 and anew communication session is established.

The location of the caller is important in emergency situations. At theoutset, the Gateway 140 utilizes the caller's location information todetermine the appropriate PSAP to receive the initial emergency textmessage. Several techniques are available for Gateway 140 to determinelocation information and provide the information to the PSAP. Forexample, Gateway 140 can query the wireless network for locationinformation of the caller, such as the cell ID, including the cell andsector currently serving the UE 110. In this example, Gateway 140 maycontain or connect to a database (not shown) that stores cell IDs andcorresponding PSAPs. In conventional emergency call networks, a databasethat stores cell IDs and corresponding PSAPs is maintained at the MPC191. In an emergency call network in accordance with an embodiment ofthe invention, a copy of the database maintained at MPC 191 also may bemaintained at Gateway 140 to determine an appropriate PSAP forresponding to an emergency text message. Alternatively, instead ofmaintaining a copy of the database, the Gateway 140 can access thedatabase maintained at the MPC 191.

When Gateway 140 queries the wireless network, a query message istransmitted to the MPC 191. Upon receipt of the query message, the MPCsends the query message to the PDE 193. The PDE 193 is a wirelessnetwork element that obtains location measurements from the UE 110, suchas global position system measurements, or from triangulation mechanismsfrom multiple cellular towers to determine the latitude and longitude ofthe UE 110. Alternatively, Gateway 140 can send the query messagedirectly to the PDE 193 rather than sending the query message throughthe MPC 191. Gateway 140 can query the wireless network for the locationinformation of the caller upon receiving the emergency SMS text message,or at any point during the communication session with the PSAP 180.

Latitude and longitude information associated with the caller also oralternatively can be used to determine an appropriate PSAP to receive aninitial emergency message. Gateway 140 may include mapping software thatsuperimposes a set of polygons that represent the service boundary ofeach PSAP on a map. Using the latitude and longitude informationassociated with a caller, the mapping software can determine thepresence of the caller within one of the polygons, and an appropriatePSAP can be identified.

The PSAP 180 can also request the caller's location. To request thecaller's location, the PSAP 180 sends a query message to the ALI 192(using the pANI assigned to establish the communication session toidentify the caller, see below). The ALI 192 can route the query messageto the VPC 150. In turn, the VPC 150 routes the query to Gateway 140. Inturn, the Gateway 140 queries the wireless network, as discussed above.Alternatively, the ALI 192 can send the query message to the MPC 191 orPDE 193 directly. Once received, the PSAP 180 can display the locationinformation of the caller on the call taker's workstation (not shown) ona map or text containing an approximate street address.

In these examples, location information is returned to the requesterusing the same path used to send the query message. The locationinformation can be requested once or repeatedly during a communicationsession. The caller's location information can be the caller's actuallocation or the location of the cell and sector currently serving thecaller.

To establish an audio call, such as a VoIP call, with a PSAP, theGateway 140 selects a “pseudo ANI” (or “pANI”), which is a telephonenumber, from a pool of telephone numbers that can be maintained atGateway 140 for each PSAP. Gateway 140 establishes an audio call, suchas a voice over internet protocol (VoIP) call, to 9-1-1, using the pANIas the calling party number. As discussed above, Gateway 140 maintains atable of communication sessions with the telephone number of the callerfor each session. This table can also include the pANI used for eachcommunication session.

In the embodiment of the invention as depicted in FIG. 2A, Gateway 140transcodes the signaling between UE 110 and PSAP 180 via an audio call,such as a VoIP audio call. In a VoIP implementation, the communicationsession between the Gateway 140 and the PSAP 180 is routed through theVPC 150, ESGW 160, and 9-1-1 SR 170. The VPC 150 routes the call to anemergency services gateway network, which routes the call to ESGW 160based on the pANI. Next, the ESGW 160 routes the call to a 9-1-1 SR 170based on the pANI. Lastly, the 9-1-1 SR 170 can route the call to thePSAP 180 based on the pANI.

As is known, the PSAP 180 answers the call and directs it to one of itscall takers. Once the communication session has been established, theGateway 140 can send the emergency SMS text message to a TTY-configuredPSAP 180 using tones such as Baudot tones. The call taker, upon hearingthe tones, connects its TTY to the communication session. The tones arerendered as text to the call taker. The call taker can reply to theemergency SMS text message using TTY. Accordingly, the PSAP 180 canreceive Baudot tone messages and can transmit reply messages in the formof Baudot tone messages. The Gateway 140, upon receipt of the reply tonemessage can generate a reply SMS text message corresponding to the replytone message. Once the reply SMS text message is generated, it can berouted back to the UE 110.

During the communication session, the caller and the call taker can sendmessages to each other. Each message from the caller is received as anSMS text message by the Gateway 140, and routed to the PSAP 180 in thesame manner as with the initial message. The Gateway 140 routes SMSmessages from the caller, which are identified by the telephone numberof the caller, to the PSAP 180 using Baudot tones on the communicationsession established for the caller. The PSAP 180 receives these tonemessages from the caller using TTY. The call taker can reply to thecaller using reply tone messages. The reply tone messages of the calltaker can be routed to the Gateway 140 on the communications sessionpreviously established for this caller. The reply tone messages arereceived by the Gateway 140 as Baudot tones. The Gateway 140 cangenerate reply SMS text messages corresponding to the reply tonemessages that are sent to the caller's UE 110.

Once the call taker determines that the communication session should beterminated, the PSAP 180 terminates the communication session with theGateway 140. Upon receipt of a termination message from the PSAP 180,the Gateway 140 can release the pANI for use in another call. Anysubsequent SMS text messages from the same caller will be treated as anew conversation, and a new communication session can be established.

In addition to being able to send a SMS text message to the PSAP 180, inaccordance with an exemplary embodiment, the caller additionally cansend a multimedia message service (MMS) message, including a picture orvideo clip, to 9-1-1. The Gateway 140 receives the MMS message in asimilar manner as an SMS text message. A MMS message can also containtext content that accompanies the picture or video clip. The textcontent of a MMS message can be routed to the Gateway 140 using Baudottones, as described above for a SMS message.

To send the media portion of the MMS message to the PSAP 180, theGateway 140 can route a media alert message to the PSAP 180 using Baudottones on the communication session that alerts the PSAP 180 to theavailability of the picture or video clip. The Gateway 140 may includean Internet server that hosts multimedia to be retrieved by the calltaker at PSAP 180. The media alert message can contain a retrieval code,URL, or other mechanism for accessing the picture or video clip from theGateway 140. The call taker at PSAP 180 can view the picture or videoclip at the call taker's computer station using a web browser, forexample.

Because some PSAPs may not be configured for accessing a picture orvideo message, the Gateway 140 contains a list of PSAPs configured toretrieve multimedia. When the PSAP cannot retrieve multimedia messages,the Gateway 140 can send the caller a “no-media” message informing thecaller that the PSAP cannot accept pictures or video.

Although an emergency message typically originates with a caller, in anexemplary embodiment, the call taker can also establish a communicationsession to communicate with a caller. For example, if a communicationsession is disconnected due to a loss in cellular service of the caller,the call taker can seek to establish a new communication session. Inthat manner, the call taker can re-establish a communication session byplacing an audio telephone call to the associated Gateway 140. After theGateway 140 acknowledges the communication session with the PSAP 180,the PSAP 180 sends an identifying code, such as the telephone number ofthe caller it wishes to communicate with. Once again, information iscommunicated between the Gateway 140 and the PSAP 180 using Baudottones. The Gateway 140 can acknowledge receipt of the identifying codeby sending a message to the PSAP 180. The PSAP 180 can send a messageintended for the caller using its TTY. The Gateway 140 receives themessages as Baudot tones. As discussed above, the Gateway 140 sends anSMS message to the caller containing the content of the tone messagereceived by the Gateway 140 from the PSAP 180.

If the caller receives a message originated from PSAP 180 and chooses toreply, the SMS text reply message can be received by the Gateway 140 andcan be routed to the PSAP 180 using a Baudot tone message. As discussedabove, the caller communicates using SMS text messages, and the calltaker communicates using TTY, in which the Gateway 140 bidirectionallytranscodes between the two message formats. Once the call taker at PSAP180 terminates the communication session with the Gateway 140, anysubsequent messages from the caller will prompt a message from theGateway 140 that the communication session has ended. Alternatively, anew communication session can be established.

Although FIG. 2A illustrates an exemplary implementation of emergencycall network, the invention is not limited thereto, and otherimplementations for establishing a communication session are possible.For example, the communication session may be a VoIP call, but theinvention is not limited to VoIP implementations as other audio calltechnologies can be used. In another example, the VPC 150 and ESGW 160can be replaced by a proxy server and gateway server, respectively, asshown in FIG. 2B. In yet another example, the Gateway 140 establishes acommunication session with the SR 170 directly, as shown in FIG. 2C. Inyet another example, the communication session can be routed to the SR170 through a MSC disposed between the Gateway 140 and SR 170, as shownin FIG. 2D.

FIG. 3 is a block diagram that illustrates an exemplary gatewayaccording to an embodiment of the present invention. The Gateway 140 isa computer having several hardware and software components thatimplement its functions.

The CPU 241 and memory 242 are conventional hardware components of acomputer. The CPU 241 and memory 242 can be utilized by other componentsof the Gateway 140, the components communicating over a conventionalcommunications bus or other communications means.

The receiver 243 and transmitter 245, and communicator 244 are softwarecomponents of the Gateway 140. The receiver 243 and transmitter 245 useone or more communications ports of the Gateway 140 to bi-directionallycommunicate SMS text messages with the SMSC 130 (shown in FIG. 2A) usingshort message peer to peer protocol (SMPP). The receiver 243 andtransmitter 245 can be implemented or referred to as separate softwarecomponents or as an integrated transceiver (not shown).

Similar to the receiver 243 and transmitter 245, the communicator usesone or more communications ports of the Gateway 140 to establish anaudio call with the VPC 150 (shown in FIG. 2A). Session initiationprotocol (SIP) is used to establish a VoIP call with the VPC 150 (shownin FIG. 2A). The communicator 244 establishes and maintains acommunication session with the PSAP 180. The communicator 244 can alsoreceive incoming calls from the PSAP 180.

The remaining components of the Gateway 140 are also primarilyimplemented as software components. The communications manager 246 is asoftware application that manages communication sessions for the Gateway140. Upon receipt of a SMS text message, the conversation manager 246can determine whether the message originates from a telephone numberwhich is or is not currently in a communication session. Thecommunications manager 246 can maintain a table of communicationsessions with the telephone number of the caller for each session. Whena message is received, the communications manager 246 checks thetelephone number of the message sender against the telephone numbers ofthe existing communication sessions. If needed, the communicationmanager 246 can establish a new communication session with the PSAP 180through the communicator 244.

In addition, conversation manager 246 receives updates with respect tothe status of communication sessions. For example, communicator 244 cannotify the conversation manager 246 of the status of a communicationsession such as the termination of a communication session. In anotherexample, the conversation manager 246 can verify a communication sessionwith the PSAP 180 by sending a preprogrammed message to the PSAP 180 andreceiving an authorization message in response to the preprogrammedmessage.

As discussed above, the caller's location information is used by theGateway 140 to determine which PSAP should receive the SMS text message.The router 251 is a software application that is invoked by conversationmanager 246 to query the wireless network for the caller's locationinformation, such as a cell ID. Queries for the cell ID are sent to theMSC 120. Alternatively, the MPC 191 or PDE 193 can be queried for thecaller's location. The caller's location information can be the caller'sactual location or the location of the cell and sector currently servingthe caller. The router also accesses a mapping that associates locationinformation, such as cell ID, to the PSAP that should get the initialSMS text message that is stored in Gateway 140.

As also discussed above, a pANI is assigned to the UE. The pANI manager249 is a software application that is invoked by the conversationmanager 246 to assign a pANI to the caller. A pool of pANIs ismaintained for each PSAP. When a communication session is established,and which PSAP should get the call is determined based on the locationof the caller, a pANI is allocated from the pool associated with thatPSAP. The pANI is associated with the communication session and isplaced in the signaling to the PSAP establishing the audio call. Upontermination of the communication session, the pANI and other allocatedresources can be released.

The transcoder 247 is a software application that bi-directionallytranslates between text message and tone message formats, such as Baudotor ASCII tones. SMS text messages received from the receiver 243 can betranscoded to tones. Similarly, tone messages received on thecommunication session with the PSAP 180 can be transcoded to SMS textmessages. At the receiver 243, SMS text messages from the caller can bequeued and routed to the transcoder 247. At the transmitter 245, SMStext messages originating from call taker can be received from thetranscoder 247 and can be routed to the caller.

The Gateway 140 also includes a media manager 248 that is a softwareapplication that receives MMS messages containing one or more picturesor videos. For MMS messages, media manager 248 can store the media, andcan generate a message containing a retrieval code or URL that can berouted to the call taker. In other words, the media manager 248 caninvoke the Internet server 253 that is a software application thatenables the Gateway 140 to function as an Internet server. The Internetserver 253 also stores the pictures and videos contained in MMSmessages, and makes them accessible to the call takers using a retrievalcode or URL. For example, the call taker at PSAP 180 can retrieve thepicture/video with the retrieval code and/or by accessing a URL. SomePSAPs may be unable to access a picture or video message. Accordingly,this functionality can provisioned on or off per PSAP. When off, thePSAP can route a no-media message to the media manager 248 of theGateway 140.

The location manager 250 is a software application that handles requestsfor the caller's location information received from the PSAP 180. Thelocation manager 250 may be invoked by the PSAP 180 at any time duringthe communication session. In order to retrieve the caller's location,the location manager 250 invokes the router 251 to query the wirelessnetwork. When a location query is received by the location manager 250,the pANI in the query is used to identify the communication session.

The maintainer 252 is a software application that monitors and maintainsthe functionality of Gateway 140. The maintainer 252 can perform healthchecks and provide network monitoring functions for Gateway 140. Inaddition, the maintainer can also provide provisioning capability forthe network, PSAP, pANI, cell id and other mapping tables in thegateway.

FIG. 4 is a flow diagram that illustrates an exemplary method forconnecting with a public safety answering point according to the presentinvention.

At step 401, the Gateway 140 receives a caller's emergency text message.Upon receipt of the emergency text message, the Gateway 140 determineswhether the emergency text message is part of an existing communicationsession. Here, the Gateway 140 checks the telephone number of themessage sender against the telephone numbers of the existingcommunication sessions. When the emergency text message is determined tobe part of an existing communication session, the Gateway 140 associatesthe text message with the communication session of the caller, as shownat step 421. On the other hand, when the emergency text message isdetermined not to be part of an existing communication session, theGateway 140 queries the wireless network for the caller's locationinformation, such as the caller's cell ID, at step 422. With thecaller's location information, the Gateway 140 identifies a responsivePSAP 180 to receive the emergency text message, as shown at step 423.Next, at step 424, the Gateway 140 establishes a new communicationsession between the caller and the call taker at responsive PSAP 180.

After the emergency text message is associated with an existingcommunication session (step 421) or a new communication session isestablished (step 424), the Gateway 140 generates an emergency tonemessage corresponding to the emergency text message at step 430. TheGateway 140 then routes the emergency tone message to the responsivePSAP 180 at step 440. Next, at step 450, the Gateway 140 receives areply tone message from the responsive PSAP 180. In turn, the Gateway140 generates a reply text message corresponding to the reply tonemessage, at step 460. Lastly, the Gateway 140 routes the reply textmessage to the caller at step 470.

As can be understood from the above description, the present inventioncan use TTYs to provide SMS capability by interworking the SMS messagesystem with the TTY support system in the emergency call process, thusallowing a wireless caller to text to the PSAP in at least a similarmanner as the caller would send a text message to another UE. Similarly,the PSAP can use its TTY in a similar manner as any other TTY call.

Accordingly, the present invention is directed to a system and methodfor delivering SMS text messages to emergency call centers that exploitsexisting infrastructure. This has the advantage of allowing a rapiddeployment, with minimal cost at the PSAP, while using normal commercialelements in the origination network. The proposed system and method isadvantageous because large system upgrades are not required.

The foregoing description serves to explain the invention by way ofexample, but it should be understood that the invention is not limitedto the exemplary embodiments described herein. For example, although theinvention is described within the context of emergency call centers, itis equally applicable to non-emergency services such as 3-1-1 servicesand the like. In addition, the invention is described as using SMS textmessaging, but is also applicable to any text service. Similarly, theinvention is described as using TTYs, but is also applicable to anytone-based system. In yet another example, although the invention isdescribed within the context of sending text messages from a cellularphone, it is equally applicable to text messages and e-mail messagesfrom smartphones, tablets, laptops, and other computing devices.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the system and method fordelivering short message service text to call centers of the presentinvention without departing form the spirit or scope of the invention.Thus, it is intended that the present invention cover the modificationsand variations of this invention provided they come within the scope ofthe appended claims and their equivalents.

What is claimed is:
 1. A communications system comprising: a gateway forrouting communications between callers' mobile communications devicesand call centers, the gateway being configured to: translate an incomingcommunication that is based on a text message generated by a caller'smobile communications device into a tone-based message for receipt by acall center, wherein a first format of the text message generated by thecaller's mobile communications device is different from a second formatof the tone-based message; and determine whether the incomingcommunication is an initial message or is otherwise part of an existingcommunication session, such that the gateway routes the translatedtone-based message that is a part of an existing communication sessionto the call center handling the existing communication session, whereinthe message generated by the caller's mobile communications device is amultimedia message service (MMS) message having a multimedia content,and wherein the tone-based message includes tone-based data alerting thecall center that the multimedia content is available.
 2. Thecommunications system of claim 1, wherein the gateway comprises a tableof communication sessions with an identifier of the caller for eachcommunication session, and wherein the gateway determines whether theincoming communication is an initial message or is otherwise part of anexisting communication session by accessing the table.
 3. Thecommunications system of claim 1, wherein the multimedia content isstored at the gateway such that the content is retrievable by the callcenter.
 4. The communications system of claim 1, wherein the tone-basedmessage is a teletypewriter (TTY) message.
 5. The communications systemof claim 1, wherein the incoming communication is received from anintermediary entity between the caller's mobile communications deviceand the gateway.
 6. The communications system of claim 5, wherein theintermediary entity is a short message service center (SMSC).
 7. Thecommunications system of claim 5, wherein the incoming communicationincludes at least a portion of the text message generated by thecaller's mobile communications device and an additional informationgenerated by the intermediary entity.
 8. The communications system of36, wherein the additional information is a destination identifierassociated with the gateway.
 9. The communications system of claim 1,wherein termination of the existing communication session is controlledby the call center.
 10. The communications system of claim 9, whereinthe existing communication session is terminated after receiving atermination request from the call center.
 11. A method of text messagingbetween a caller's mobile communications device and a call center via agateway, comprising: receiving an incoming communication that is basedon a text message generated by the caller's mobile communicationsdevice; generating a tone-based message for receipt by the call centerbased on the incoming communication, wherein a first format of the textmessage generated by the caller's mobile communications device isdifferent from a second format of the tone-based message; anddetermining whether the incoming communication is an initial message oris otherwise part of an existing communication session, such that thegateway routes the generated tone-based message that is a part of anexisting communication session to the call center handling the existingcommunication session, wherein the text message generated by thecaller's mobile communications device is a multimedia message service(MMS) message having a multimedia content, and wherein the tone-basedmessage includes tone-based data alerting the call center that themultimedia content is available.
 12. The method of claim 11, wherein thegateway comprises a table of communication sessions with an identifierof the caller for each communication session, and wherein thedetermination of whether the incoming communication is an initialmessage or is otherwise part of an existing communication sessionincludes accessing the table.
 13. The method of claim 11, wherein themultimedia content is stored at the gateway such that the content isretrievable by the call center.
 14. The method of claim 11, wherein thetone-based message is a TTY message.
 15. The method of claim 11, whereinthe incoming communication is received from an intermediary entitybetween the caller's mobile communications device and the gateway. 16.The method of claim 15, wherein the intermediary entity is an SMSC. 17.The method of claim 11, wherein the incoming communication includes atleast a portion of the text message generated by the caller's mobilecommunications device and an additional information generated by theintermediary entity.
 18. The method of claim 17, wherein the additionalinformation is a destination identifier associated with the gateway. 19.The method of claim 11, further comprising terminating the existingcommunication session after receiving a termination request from thecall center.
 20. A non-transitory, computer-readable storage mediumstoring instructions, an execution of which in a computer system causesthe computer system to perform operations comprising: receiving anincoming communication that is based on a text message generated by acaller's mobile communications device; generating a tone-based messagefor receipt by a call center based on the incoming communication,wherein a first format of the text message generated by the caller'smobile communications device is different from a second format of thetone-based message; and determining whether the incoming communicationis an initial message or is otherwise part of an existing communicationsession, such that the gateway routes the generated tone-based messagethat is a part of an existing communication session to the call centerhandling the existing communication session, wherein the text messagegenerated by the caller's mobile communications device is a multimediamessage service (MMS) message having a multimedia content, and whereinthe tone-based message includes tone-based data alerting the call centerthat the multimedia content is available.